Prior to the early 1990's, much was known about the geochemical evolution of lavas from Mt. Erebus. Clearly, the stratigraphically oldest lavas were of a primitive basanitic composition, while the current activity is a more chemically evolved tephriphonolite. However, only a few age dates existed for the whole of Mt. Erebus and these were limited to imprecise conventional K/Ar dates. Beginning in 1993, Dr. Philip Kyle and two of his students (Chris Harpel and Richard Esser) began utilizing the more advanced, high precision 40Ar/39Ar dating technique to determine the ages of many of the exposed lava flows on Mt. Erebus. Prior to the use of 40Ar/39Ar geochronology on Mt. Erebus, what little age data existed suggested that the volcano was several million years old, including the young-looking summit area. We now know that the entire volcano is just slightly older than 1 million years old and that the summit is significantly younger than 100,000 years old.

By combining the new geochronologic data with the existing database of geochemical data, we can better confirm an evolutionary model for the development of Mt. Erebus. Below are the summarized results from several researchers working on the evolution of the volcano.

General Background

Mt. Erebus is one of several volcanoes in the McMurdo Volcanic Group which itself consists of Late Cenozoic intraplate alkaline volcanoes.

Cross-section of the crust and upper mantle below Ross Island, Antarctica. A "hot spot" or mantle plume is theorized as the mechanism to account for the origin of Mt. Erebus and Ross Island.

Below are six cartoons showing the proposed volcanic evolution of Mt. Erebus. All of the time spans (ka =1000 years) are based on 40Ar/39Ar geochronology of lava flows exposed on the summit and flanks of the volcano.